Older women who experience a hip fracture have a twofold increase in mortality risk in the first year after the fracture, researchers found.

Action Points

Note that mortality is increased in patients who experience a hip fracture, but it is not known if this is because of the fracture itself or associated comorbidities.

Point out that this study indicates that in older women, short-term mortality risk is increased in the first year after the fracture, but in women 70 years or older the risk returns to previous levels.

Older women who experience a hip fracture have a twofold increase in mortality risk in the first year after the fracture, researchers found.

During the 12 months following the fracture, 16.9% of the women died, compared with 8.4% of controls, for an odds ratio of 2.3 (95% CI 1.9 to 2.8), according to Erin S. LeBlanc, MD, of Kaiser Permanente Northwest in Portland, Ore., and colleagues. They researchers adjusted for potential confounders such as age, bone mineral density (BMD), and coexisting conditions such as diabetes, hypertension, and stroke.

And the increased mortality risk during the first year remained after further adjustment for specific hip fracture risk factors such as total hip BMD (OR 2.4, 95% CI 1.9 to 3.1), the researchers reported online in Archives of Internal Medicine.

Previous studies examining mortality after hip fracture have shown mixed results, and were limited by failing to control for comorbidities as well as overall health status.

To overcome these limitations, LeBlanc and colleagues analyzed data from the prospective Study of Osteoporotic Fractures that followed 9,700 women, ages 65 and older, for a mean of 14.4 years. Almost all were white.

Among this cohort, 1,116 had a hip fracture, each of which was matched with four controls, for a sample size of 4,464.

During the study period, 48.2% of the women died during the follow-up period.

A total of 52.4% of the deaths occurred within three months and 72.5% within six months of the fracture, according to the researchers.

By year five, 24.6% of cases and 21.9% of controls had died (OR 1.2, 95% CI 1 to 1.5), but this significant difference was lost after adjustment (OR 1.2, 95% CI 0.9 to 1.5).

Between years five and 10, 14.2% and 10% of cases and controls died (OR 1.6, 95% CI 1 to 2.6), although once again significance was lost after adjustment (OR 1.4, 95% CI 0.8 to 2.6).

Age significantly influenced mortality risk, LeBlanc's group found.

The risk was highest among women, ages 65 to 69, who had an adjusted five-fold risk during year one (OR 5, 95% CI 2.6 to 9.5).

In contrast, women ages 80 and older had no increased risk of death during the first year (OR 1.1, 95% CI 0.6 to 2.1) while those between 70 and 79 had an intermediate risk (OR 2.4, 95% CI 1.8 to 3.3), the researchers reported.

The women in their 60s continued to have higher risks after the first year. Between years one and five, 17.2% of cases in this age group died compared with 11.3% of controls (OR 1.9, 95% CI 1.1 to 3.2). During years five to 10, mortality was 12.1% and 5.9% among cases and controls, respectively (OR 3.2, 95% CI 1.0 to 10.2).

"Those who are younger and/or healthier have a low risk of dying from other causes. Therefore, experiencing a hip fracture may increase their mortality risk compared with nonfracture controls," the researchers explained.

These longer term increases were not seen for women in the older age groups.

The researchers also performed a separate analysis among very healthy women who were 80 and older, and unlike the oldest women overall, they found that this subgroup did have a three-fold increase in risk during the first year (OR 2.8, 95% CI 1.5 to 5.2).

They explained that the high mortality among women of this age presented difficulties in determining whether hip fracture conferred an independent risk.

"Our purpose in evaluating the exceptionally healthy subset was to better isolate the independent effects of hip fracture on mortality from those of comorbidities, and indeed we found an increased risk in the first year after hip fracture compared with similarly healthy age-matched controls," observed LeBlanc and colleagues.

Death rates were similar among cases and controls for heart disease, stroke, and sepsis. More women with fractures died of pneumonia (10.5% versus 5.6%, P<0.001) and following an osteoporotic fracture (2% versus 0%, P<0.001).

Mortality associated with cognitive disorders also was greater in cases than controls (9.2% versus 6.7%, P=0.03), while cancer deaths were more common among controls (18.2% versus 11%).

The researchers concluded that the incidence of hip fracture is likely to increase in the coming decades, and that particular preventive efforts should focus on women, ages 60 to 69, because of their significantly elevated risks.

Limitations of the study included its homogeneous population and the possibility of confounding by other comorbidities or frailty in general.

The study was funded by the National Institute of Arthritis and Musculoskeletal and Skin Diseases and the National Institute on Aging. The lead author is supported by the National Center for Research Resources.

The authors had no financial disclosures.

Reviewed by Zalman S. Agus, MD Emeritus Professor, Perelman School of Medicine at the University of Pennsylvania and Dorothy Caputo, MA, BSN, RN, Nurse Planner

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